Soursop for Cancer: The Science & Why It Scores 3/10

Apr 15, 2025

Traditional Use of Soursop (Graviola)

Soursop Annona muricata – also known as graviola, guanábana, or Brazilian pawpaw – is a tropical fruit tree native to the rainforests of Africa, South America, and Southeast Asia [1] For generations, people in these regions have used various parts of the soursop plant (fruit, leaves, roots, and seeds) as folk medicine. Traditional healers prized soursop for treating ailments like inflammation, infections, and other illnesses. [1] In some cultures, soursop leaves and fruit have even been used as a folk remedy for cancer, long before modern medicine took notice. [2] This rich history of use – combined with the fruit’s sweet tropical flavour – has contributed to Soursop’s reputation as a natural wellness panacea.

In recent years, soursop has been widely promoted on the internet as a potential alternative cancer treatment.[3] Enthusiasts often point to its use in traditional medicine and preliminary research findings as reasons to try soursop for cancer. It’s not uncommon to see exotic claims – for example, some viral posts even allege that soursop is “10,000 times stronger than chemotherapy.” However, experts strongly caution that these claims are not backed by science. [4] To understand why Antioxi remains sceptical (rating soursop extract just 3/10), we need to examine what modern research actually says about soursop leaves and cancer.

What Does the Science Say? (In Vitro vs. In Vivo Evidence)

Laboratory Studies (In Vitro): A number of laboratory studies have tested soursop extracts on cancer cells in petri dishes, and many of the results sound promising. Compounds in soursop (notably a group of substances called annonaceous acetogenins) can kill or inhibit growth of several types of cancer cells in the lab.[2] For example, graviola leaf extracts have shown activity against breast cancer cells – inducing them to undergo normal cell death (apoptosis) – as well as against liver, lung, pancreatic, prostate, and colon cancer cell lines. [2] In these controlled lab settings, soursop compounds appear to:

Trigger cancer cell death: Soursop extracts can push cancerous cells to die off (a process called apoptosis), a mechanism that many cancers try to evade. [2]
Block growth and metastasis: Laboratory tests show soursop may slow the proliferation of cancer cells and even prevent them from metastasizing (spreading to other tissues). [2]
Disrupt cellular function: Research suggests soursop compounds can block certain cellular pathways that tumors use for growth. For instance, graviola extracts have been noted to inhibit ATP production (the energy currency of cells) in cancer cells, effectively starving them of energy. [2] They may also scramble growth signalling pathways and downregulate proteins that cancer cells need to survive. [1]

These intriguing mechanisms explain why scientists became interested in soursop. In vitro, soursop can act like a cancer cell killer – at least in a petri dish.

Animal Studies (In Vivo): Moving from the petri dish to living organisms, there have been some in vivo experiments (primarily in mice or rats) using soursop extracts. In these animal studies, soursop has at times shown anti-cancer effects. For example, one study found that graviola leaf extract shrank breast cancer tumours in mice. [2] Other animal research noted that soursop extracts could inhibit tumour growth in skin cancer models and reduce prostate tumour size in rats. [2] These results hint that the anticancer effects of soursop seen in the lab might also occur in a living body – at least in animals.

However, it’s important to emphasize that animal results don’t always translate to humans. The doses and extracts used in lab or animal studies can be very concentrated. Additionally, differences in metabolism mean that what works in a mouse may not work (or be safe) in a person. As of now, the soursop cancer research has mostly stopped at the animal stage.

Human Evidence (Or Lack Thereof): Here lies the biggest gap. To date, there are no robust clinical trials showing that soursop can treat or cure cancer in humans. [3] While laboratory and animal studies have been encouraging, scientists have not yet tested soursop on actual cancer patients in any large, peer-reviewed clinical trial. [3][4] In other words, we have test-tube and animal data, but no reliable human data demonstrating that soursop is effective against cancer. Experts at Cancer Research UK put it plainly: “Claims that graviola can treat cancer are not backed up by research. Research so far has mainly been laboratory research.” [3] Similarly, a Healthline review notes that although lab studies suggest anticancer properties, “there isn’t any clinical evidence that graviola can treat or prevent cancer in humans.” [5]

Because of this lack of human evidence, soursop remains an experimental supplement at best when it comes to cancer. It absolutely should not replace conventional cancer treatments like chemotherapy, surgery, or radiation. [2] Doctors worry when patients forego proven therapies for an unproven herb – no matter how hopeful the early lab results may seem. The bottom line from current science: soursop extracts have shown anti-cancer activity in test tubes and animals, but we don’t know if they help people with cancer. Without clinical trials, we’re essentially guessing.

Safety and Side Effects: Proceed with Caution

Even though soursop is “natural,” natural doesn’t always mean harmless. Researchers have identified several potential side effects and safety concerns with soursop, especially if used in high doses or long-term:

Nerve and Brain Effects: Perhaps the biggest red flag is soursop’s impact on the nervous system. Some chemicals in soursop might cause nerve damage and movement disorders. [3] In laboratory experiments, certain compounds from soursop triggered neuron dysfunction and changes similar to Parkinson’s disease. [3] There was even a study in the Caribbean finding that people who consumed very large amounts of soursop were more likely to develop neurological symptoms resembling Parkinson’s. [3] These findings suggest that high exposure to soursop’s active compounds could have neurotoxic effects – basically, it might harm nerve cells and the brain. [1] This is a serious concern, as Parkinson-like damage is not a trivial side effect. More research is needed to see if typical supplement doses could pose this risk in humans, but the potential for neurological side effects is a key reason for caution.
Low Blood Pressure: Soursop has been observed to cause drops in blood pressure in animal studies. [2] If you already have low blood pressure or are on blood pressure medications, taking a lot of soursop could theoretically make your blood pressure too low, leading to dizziness or fainting. This effect hasn’t been well-studied in humans, but it’s a noted concern.
Low Blood Sugar: Likewise, soursop might lower blood sugar levels. [2] Diabetics or people prone to hypoglycemia should be careful, since combining soursop with diabetes drugs could potentially push blood sugar to unsafe lows.
Liver and Kidney Concerns: There is some indication that frequent or high-dose use of soursop could be hard on the liver and kidneys. [3] We don’t have definitive proof of organ damage in humans, but animal studies raise this possibility. Until we know more, it’s wise to be mindful of potential liver or kidney strain from heavy use of soursop extracts.

On a brighter note, occasional dietary intake of soursop fruit is likely safe for most people. Enjoying a soursop smoothie or tea now and then as part of a normal diet is unlikely to harm you. [3] The concerns above mostly apply to concentrated extracts or very high consumption over time. Even beneficial herbs can become problematic in mega-doses. So while eating the fruit as food is fine, taking strong soursop supplements in an attempt to fight cancer could carry risks we don’t fully understand yet.

Given these safety flags and the lack of proven benefits, medical experts generally do not recommend soursop as a cancer therapy. Memorial Sloan Kettering Cancer Center, for instance, notes that graviola is widely promoted to cancer patients despite a lack of clinical evidence, and urges caution pending more research. [1] Until rigorous studies in humans show not only efficacy but also safety, it’s best to approach soursop with healthy scepticism. Always talk to your doctor first if you’re considering trying soursop (or any alternative remedy) during cancer treatment. [3]

Antioxi’s Rating: Why Soursop Gets a 3/10

At Antioxi, we evaluate natural compounds by looking at both the strength of evidence and the safety profile. Soursop extract scores only 3 out of 10 in our rating system – indicating very low confidence as a cancer remedy. Here’s why the rating is this low:

Lack of Human Evidence (Major Drawback): Soursop’s anti-cancer reputation rests on petri dish and animal experiments. There are no well-controlled studies in actual cancer patients demonstrating benefit. [3][5] This means we have no proof that it works in the real world. In evidence-based rating terms, soursop is missing the highest levels of evidence (human trials), which heavily drags down its score. At best, it’s an unproven hope; at worst, it’s an ineffective distraction.
Potential Risks > Unknown Benefits: Because we don’t know if soursop helps, any significant risk is a big strike against it. The concern about neurological toxicity (nerve damage) is a serious one. [3] The possibility of other side effects (blood pressure, liver, kidney issues) also raises red flags. With a medication, we tolerate risks if there’s a clear benefit. But in soursop’s case, the benefits aren’t proven – so taking on risk makes little sense. This imbalance (unknown benefit vs. known potential harm) is another reason for the low 3/10 rating.
No Regulatory Approval or Clinical Use: Unlike some herbal extracts that have made it into clinical practice in certain countries, soursop is not an approved cancer treatment anywhere. No major cancer organization or hospital recommends it as a treatment. [3] In fact, reputable cancer institutes outright state that there’s no evidence to support soursop as a cure. [3] This consensus in the medical community that soursop should not be used as a cancer therapy reinforces our cautious stance. A 3/10 reflects that mainstream medicine currently finds soursop largely unsupported as a cancer remedy.

In summary, Antioxi gives soursop a 3/10 because the science isn’t there yet, and there are enough safety questions to make us hesitant. It might have a place in the future if research catches up, but right now, using soursop for cancer is walking on thin ice. We encourage readers to view soursop as an “experimental” supplement – not a proven solution.

Comparing Soursop with Turkey Tail Mushroom (Graviola vs. Trametes versicolor)

It’s helpful to put soursop in context by comparing it to another popular natural remedy that’s used in integrative cancer care: turkey tail mushroom extract. Both soursop and turkey tail are derived from plants (well, a fruit tree vs. a fungus) and both have been studied for potential anti-cancer properties. However, Antioxi rates turkey tail much higher – 7.5/10 – reflecting stronger evidence and safety. Let’s explore why turkey tail mushrooms are considered a better-supported integrative aid for cancer, and how they stack up next to soursop:

Evidence Base

Turkey Tail: Turkey tail (Trametes versicolor, also known as Coriolus versicolor) has a remarkable body of research behind it. This mushroom has been used for centuries in traditional Asian medicine, and in modern times it’s been incorporated into cancer treatment in places like Japan. [6] The key components are polysaccharide compounds (like PSK – polysaccharide Krestin – and PSP) which are extracted from the mushroom. These have been studied in numerous clinical trials as adjuncts to conventional cancer therapy. For instance, a review of 11 clinical trials (plus additional lab studies) found that adding PSK from turkey tail improved survival in lung cancer patients receiving radiation. [7] Another analysis, covering over 8,000 patients with gastric cancer, found that those who received turkey tail extract alongside chemotherapy lived longer than those who didn’t. [7] In Japan, PSK from Turkey Tail is actually an approved medicine given to cancer patients to help boost their immune response and improve outcomes. [6] There is also early research in the U.S. and elsewhere – including a Phase I trial in breast cancer survivors – suggesting turkey tail preparations are safe and may benefit immune function. [6] In short, Turkey Tail’s anti-cancer claims are backed by multiple human studies, something Soursop completely lacks.
Soursop: By comparison, soursop’s evidence is largely limited to test tubes and rodents, with no clinical trials in humans showing a benefit. [5] While soursop can claim dozens of lab studies showing it kills cancer cells, it cannot claim, say, a trial where cancer patients lived longer or their tumours shrank due to soursop. Turkey Tail can point to exactly those kinds of results in peer-reviewed research. [7] This stark contrast in evidence is a primary reason Turkey Tail gets a 7.5/10 rating – it has a foundation of human clinical data – whereas Soursop gets 3/10.

Role in Cancer Care

Turkey Tail’s Integrative Use: Turkey tail is typically used as an integrative support, meaning it’s given alongside standard treatments (not as a replacement). Oncologists in some countries use it to help support the immune system during chemo/radiation. Research suggests turkey tail extracts may enhance the body’s immune response, possibly helping patients tolerate treatment better and recover immune function faster. [8] Studies have indicated that patients receiving turkey tail had improvements in immune markers and, in some cases, better overall survival outcomes. [7] Integrative medicine specialists (including some in Western cancer centers) have taken note; there are reports of doctors recommending turkey tail supplements to certain patients as part of a comprehensive care plan. [8] Importantly, turkey tail is not promoted as a standalone cure – it’s seen as a complementary therapy that “tails” onto conventional treatment (pun intended!). This complementary approach is supported by research and decades of clinical use in Asia.
Soursop’s Position: Soursop, on the other hand, currently does not have an established role in mainstream or integrative cancer care. Since there’s no clinical evidence and no approval, oncologists generally do not include soursop as part of treatment protocols. Any use is patient-driven or anecdotal. It’s not part of standard integrative oncology regimens, whereas turkey tail (and other medicinal mushrooms) increasingly are. Essentially, turkey tail has made it into the toolbox of integrative cancer therapy; soursop remains outside, awaiting credible evidence.

Safety Profile

Turkey Tail: Another reason for turkey tail’s stronger reputation is its safety profile. Turkey tail mushrooms are edible and have been consumed as tea or food for ages. Modern studies indicate that turkey tail is generally safe and well-tolerated. For example, trials using doses up to 9 grams per day found it was safe, with minimal side effects. [6] Reported side effects tend to be mild, such as digestive upset (nausea, gas, or darkened stools)healthline.com. Allergic reactions can occur in people who are allergic to mushrooms (so that’s a consideration), but serious adverse effects are rare. Overall, most people handle turkey tail extracts without problems, and it’s considered a low-risk supplement. [7] This confidence in safety comes from both traditional consumption and modern clinical monitoring.
Soursop: In contrast, soursop’s safety is more questionable. As we discussed, there are concerns about neurological toxicity and other potential harms with soursop, especially if taken in high doses or long-term. [3] We lack long-term safety studies in humans for soursop supplements, so there’s a lot of uncertainty. You don’t see analogous red flags with turkey tail – no one is suggesting turkey tail causes Parkinson-like damage, for instance. This difference makes turkey tail a more comfortable choice from a safety standpoint.

To summarize the comparison: Turkey tail mushroom extract has stronger scientific support and a better-established safety record than soursop. Turkey tail has been tested in humans and integrated into cancer care (as an adjunct), whereas soursop is still unproven in people and carries more caution. Antioxi’s higher rating for turkey tail (8/10) reflects this – we view it as a promising, evidence-backed integrative therapy for supporting patients, while soursop (3/10) is an intriguing but unproven folk remedy with notable risks.

Interpreting Natural Remedy Claims: A Science-Backed Caution

It’s easy to get excited about headlines and anecdotes claiming a certain leaf or mushroom can “cure cancer.” Natural remedies like soursop and turkey tail often come with a compelling story – ancient use, miraculous lab results, and glowing testimonials. But as responsible health consumers, we need to interpret such claims with caution and scientific perspective.

Here are a few guiding principles:

Lab Results ≠ Clinical Proof: Test-tube studies are just the first step in a long research journey. Many substances can kill cancer cells in a petri dish – even bleach can, and that doesn’t mean you’d ingest it! Until a remedy is tested in humans through clinical trials, we cannot assume it will work the same way in the human body. [5] Soursop is a prime example: exciting lab results, but no clinical proof yet. [5] Always ask, “Has this been tested in people?” before believing efficacy claims.
Consider the Whole Evidence: If there are human studies, look at what they show. In the case of turkey tail, the human evidence is positive but still as a complement to standard care, not a solo cure. With soursop, human evidence is absent or purely anecdotal. Be wary of cherry-picked information. Reputable sources (oncologists, cancer organizations) consistently state that soursop is not a proven treatment. [3] When virtually all cancer experts and organizations do not endorse a supposed cure, that’s a red flag that more research is needed.
Safety First: Even “natural” substances can have side effects. Always check for known risks. If a claim sounds too good (e.g., “cancer cure with zero side effects”), be sceptical. We’ve seen that soursop can potentially cause serious side effects, and even turkey tail, while safe for most, can interact with the immune system in complex ways. [8] It’s crucial to consult healthcare professionals before adding any supplement to your regimen, especially if you have cancer. They can help weigh potential benefits and risks in the context of your overall treatment plan.
Supplement Quality and Regulation: Another point to remember is that supplements are not as tightly regulated as pharmaceuticals. The potency and purity of something like soursop or mushroom extract can vary widely by brand. [7][8] So even if the science supports a certain dose of an extract, the pill you buy might not reliably deliver it. Stick to reputable manufacturers and involve your doctor in vetting products.

In conclusion, natural remedies like soursop leaves and turkey tail mushrooms occupy an intriguing space in cancer care – somewhere between hope and hype. Antioxi’s 3/10 rating for soursop extract reflects our stance that, as of now, soursop is more hype than proven help. Turkey Tail’s 8/10 rating shows more promise – it has a role as an integrative support, grounded in better evidence. But even turkey tail is complementary, not a standalone cure.

Staying informed with scientifically grounded information is the best way to navigate claims about “natural cancer cures.” We encourage readers to approach any remedy with curiosity and caution. Nature can indeed provide powerful compounds (many chemotherapy drugs originated from plants, after all!), but it requires rigorous science to separate genuine breakthroughs from false hope. Soursop leaves might one day yield a useful medicine – but until clinical science catches up, healthy scepticism and reliance on proven treatments remain essential.

Always discuss with your doctor before trying new supplements, and remember that integrative medicine works best as a partnership between natural products and evidence-based care. Your health decisions should be friendly to innovation, but firmly grounded in research – just like the tone of this blog.

Stay informed, stay safe, and be well!