Rick Simpson Oil (RSO) and Cancer: What the Science Really Says

Rick Simpson Oil (RSO) is a concentrated cannabis extract high in THC, popularized by Rick Simpson for its alleged anti-cancer effects. While countless personal stories claim tumor shrinkage and symptom relief, you may wonder: does RSO actually work for cancer? Here’s a clear, evidence-based look.

What Is Rick Simpson Oil (RSO)?

• A homemade, solvent-based extract of cannabis.
• Very high in THC (sometimes 60–90%) plus other cannabinoids and terpenes.
• Named after Rick Simpson, who in 2003 claimed it cured his basal cell carcinoma.
• Typically taken orally or applied topically in large doses.

How Cannabinoids Might Fight Cancer

Laboratory and animal studies suggest certain cannabinoids can:

1. Trigger cancer cell death (apoptosis)
2. Slow tumor growth (anti-proliferative effects)
3. Reduce blood vessel formation in tumors (anti-angiogenesis)
4. Block signals that drive cancer spread (anti-metastatic effects)

Key studies:

• Massi et al. (2013) “Cannabidiol as a potential anticancer drug” (Br J Clin Pharmacol, PMID 22549284)
  • Focused on cannabidiol (CBD), not THC.
  • Showed CBD can induce apoptosis and block cancer cell proliferation in lab dishes.
  • Highlighted effects on breast, brain, colon and lung cancer cell lines via multiple molecular pathways (e.g., oxidative stress, modulation of cannabinoid receptors).

• Caffarel et al. (2015) “Cannabinoids reduce ErbB2-driven breast cancer progression” (Oncogene, PMID 24825245)
  • Used a mouse model of HER2-positive breast cancer.
  • Demonstrated that THC-like cannabinoids reduced tumor growth by inhibiting the AKT/mTOR signaling pathway.
  • Stressed that purified cannabinoids were administered under controlled doses.

What We Don’t Know Yet

• No large human clinical trials of RSO for any cancer type.
• Almost all positive data come from cell cultures or animal models.
• RSO is a mix of dozens of compounds; it’s unclear which ingredients—and at what doses—might have an effect.
• Dosing is unstandardized. Most protocols call for several grams per day, far higher than typical medical cannabis use.
• Variability in preparation methods means potency and purity can differ widely, increasing risk.

Anecdotes vs. Rigorous Trials

Anecdotal reports of cancer remission when using RSO can feel compelling. However:

• Cancer is unpredictable; spontaneous remissions, effects of surgery, radiation, chemotherapy or other herbs/confounding factors may play a role.
• Placebo effects or reporting bias can magnify perceived benefits.
• Without randomized controlled trials, it’s impossible to isolate RSO’s contribution.

Potential Benefits Reported by Users

• Pain relief and improved appetite.
• Nausea control, especially during chemotherapy.
• Mood enhancement and reduction of anxiety.
• Quality-of-life improvements in advanced disease.

Possible Risks and Side Effects

RSO is not risk-free. Consider:

• Psychoactive effects
– Intense “high,” sedation, short-term memory issues.
– May impair driving or daily activities.

• Digestive upset
– Nausea, diarrhea, stomach pain, especially at very high doses.

• Immune modulation
– High doses of THC can suppress immune function, potentially problematic in cancer patients.

• Drug interactions
– THC and CBD interfere with liver enzymes (CYP450 system).
– Watch for interactions with chemotherapy, immunotherapy, anticoagulants and other meds.

• Liver concerns
– Any concentrated oil extract can stress the liver.
– If you have liver disease or are at risk, consider doing a free, online “symptom check for Liver Cancer.”

Key Point: If you notice persistent fatigue, abdominal pain, jaundice or unexplained weight loss, take a moment to do that symptom check for Liver Cancer.

Guidance for Patients Considering RSO

1. Speak to a doctor
   • Never replace proven cancer treatments (surgery, radiation, chemotherapy, immunotherapy) with RSO.
   • Discuss potential benefits, side effects and drug interactions.

2. Seek quality control
   • If you choose to try RSO, use a lab-tested product from a reputable source.
   • Avoid homemade extracts prepared with improper solvents (e.g., non-pharmaceutical grade alcohol).

3. Monitor your health
   • Keep track of symptoms, lab values and imaging results.
   • Report any new or worsening signs (e.g., pain, changes in liver enzymes) to your medical team immediately.

4. Be realistic
   • Current evidence does not prove RSO cures cancer in humans.
   • Improvements in comfort and quality of life are more likely than dramatic tumor shrinkage.

5. Combine thoughtfully
   • Some studies suggest cannabinoids can boost the effects of chemo or radiation in lab settings—yet this is far from confirmed in people.
   • Always check with your oncologist before adding RSO to your regimen.

When to Get Medical Help

Any of these signs could be life-threatening:

• Sudden, severe abdominal pain
• Unexplained jaundice (yellowing of skin or eyes)
• Persistent vomiting or diarrhea
• Difficult breathing or chest pain
• New neurological symptoms (confusion, seizures)

If you experience these, seek immediate medical attention. For concerns about liver health or cancer risk, you might also consider a free, online “symptom check for Liver Cancer.”

Bottom Line

• Rick Simpson Oil (RSO) contains high levels of THC and other cannabinoids that, in lab and animal studies, can slow cancer cell growth and trigger apoptosis.
• There are no robust human trials proving RSO cures or even effectively treats cancer.
• Anecdotal reports are intriguing but not a substitute for clinical evidence.
• RSO carries potential side effects—especially psychoactive effects, immune suppression, liver strain and drug interactions.
• Always speak to a doctor before using RSO or any cannabinoid product for cancer. Serious decisions about your treatment should be made with your medical team.

Remember: your best source of personalized advice is a qualified oncologist or integrative medicine specialist. If you have any new or concerning symptoms, don’t wait—speak to a doctor right away.