Spleen supplements — usually made from freeze-dried bovine or porcine spleen — are marketed as powerful immune system enhancers, red blood cell boosters, and nutrient-dense “ancestral” foods. Advocates claim that the peptides and compounds in spleen tissue can improve immunity, fight infections, and even enhance athletic performance.
The marketing often leans on two narratives: the “like supports like” philosophy (the idea that eating an animal’s spleen will strengthen your own) and the fact that the spleen is rich in certain peptides and minerals. However, there is no clinical evidence showing that taking spleen in capsule or powder form produces these claimed benefits in humans. Most of what’s promoted is based on animal studies, nutrient charts, or anecdotal reports — not peer-reviewed, controlled human trials.
As Harvard Health Publishing explains, the “like supports like” belief has no scientific basis, and health claims for organ-derived supplements should be evaluated using modern clinical research standards.
In this article, we’ll explore where spleen supplement claims come from, what’s actually in them, what the science says (and doesn’t say), the potential risks, and the evidence-based alternatives that can provide the same benefits without the hype or hazards.
Where the Claims Come From
Spleen supplements are sold on the back of a mix of traditional beliefs, selective science, and heavy marketing — most of which doesn’t hold up under scrutiny.
→ The “Like Supports Like” Philosophy – The idea that eating an animal’s spleen will strengthen your own spleen function is an old naturopathic belief that persists in modern supplement marketing. While it may sound logical, there’s no scientific mechanism or clinical trial data supporting this.
According to Harvard Health Publishing, there is no credible evidence that consuming an animal organ confers organ-specific benefits in humans.
→ Historical & Cultural Use – In traditional diets, organ meats were eaten for their nutrient content, especially in times of scarcity. The spleen was sometimes consumed in whole food form, but this was due to availability, not because of documented health benefits.
The Price-Pottenger Nutrition Foundation notes that while organ meats were part of ancestral diets, claims about organ-specific healing are unsupported by controlled research.
→ Nutrient Density Narrative – Spleen is naturally rich in iron, certain peptides, and small amounts of vitamin B12. Brands market these nutrients as proof of immune-boosting and blood-building effects — without disclosing that capsule servings contain only a fraction of the amounts in fresh whole spleen, and without clinical evidence of actual health outcomes.
As reviewed in Nutrients, nutrient content alone cannot be used to substantiate health claims without proven clinical effect (Drewnowski & Fulgoni, 2008).
→ Influencer-Driven Marketing – Many spleen supplement brands rely heavily on testimonials and influencer promotions within the “ancestral living” niche. These endorsements often substitute anecdote for evidence, creating the perception of proven benefit where none exists.
The American Journal of Clinical Nutrition warns that anecdotal marketing can accelerate the adoption of supplements without scientific validation (Johnston, 2018).
What’s Really in Spleen Supplements
Despite being marketed as “immune superfoods” and “blood-building” organ blends, spleen supplements often contain less than consumers expect — and far less than marketing suggests.
→ Common Formulations – Most spleen supplements are made from freeze-dried (desiccated) bovine or porcine spleen, sometimes blended with other organs such as liver or thymus. While fresh spleen contains iron, small amounts of vitamin B12, and various peptides, capsule servings are a fraction of the whole-food dose.
The Journal of Food Science and Technology notes that nutrient concentrations are significantly altered during dehydration and processing (Ratti, 2001).
→ Serving Size Reality – A typical dose of 4–6 capsules provides about 2–3 grams of dried spleen powder, compared to ~100 grams in fresh spleen nutrient charts. This means marketing claims often exaggerate the nutrient impact of the supplement.
USDA FoodData Central reports that 100 g of fresh spleen contains ~44 µg of vitamin B12 and ~44 mg of iron — amounts that are rarely achieved in capsule form (USDA FoodData Central).
→ Nutrient Variability – Spleen nutrient composition varies based on the source animal’s diet, age, and health. Without standardization, the exact vitamin, mineral, and peptide content of each capsule is unpredictable.
The U.S. Pharmacopeia highlights that dietary supplements without potency and purity standards can show large batch-to-batch variability.
→ No Verified Bioactive Preservation – While marketers claim spleen peptides like tuftsin and splenopentin have immune-supporting effects, there’s no research proving these survive freeze-drying, digestion, and absorption in humans at meaningful doses.
Studies on bioactive peptides show mixed survival rates after digestion, with many degraded before reaching the bloodstream (Hartmann & Meisel, Trends in Food Science & Technology).
What The Science Says About Spleen Supplements
While spleen supplements are often promoted as immune boosters and blood-building aids, there is no direct human clinical evidence to validate these claims.
→ No Randomized Controlled Trials in Humans – There are no published randomized controlled trials evaluating freeze-dried spleen capsules for immune enhancement, red blood cell production, or athletic performance in humans. Most cited “evidence” comes from in vitro studies or animal research that cannot be directly applied to supplement use in people.
As the Cochrane Database of Systematic Reviews stresses, nutrient composition alone cannot justify health claims without proven clinical effect in human intervention trials (Higgins et al., 2019).
→ Iron & B12 Content Not Clinically Validated – While fresh spleen is high in iron and vitamin B12, no studies have measured whether capsule forms provide enough of these nutrients to meaningfully improve iron status or correct B12 deficiency.
The NIH Office of Dietary Supplements notes that supplementation should meet clinically established dosing guidelines, which cannot be assumed from organ capsule nutrient charts.
→ Immune Claims Are Unsubstantiated – Some brands point to peptides like tuftsin and splenopentin for immune function, but these compounds have not been clinically tested in humans via dietary supplementation.
A review in Immunology Letters notes that while tuftsin has demonstrated immune-modulating effects in lab settings, its bioavailability from oral organ supplements has not been studied (Najjar et al., 2015).
→ Animal Studies Do Not Equal Human Results – Research on spleen extracts in animals cannot be directly translated to human health claims due to differences in dosage, metabolism, and delivery methods.
The American Journal of Clinical Nutrition cautions against extrapolating animal data to human supplement use without supporting clinical trials (Johnston, 2018).
Potential Downsides & Red Flags
While marketed as “nutrient-dense” and “immune-supporting,” spleen supplements can carry significant risks — especially when taken daily without medical oversight.
→ Excess Iron Intake – Spleen is naturally high in heme iron. In concentrated capsule form, chronic use could contribute to iron overload, which is linked to oxidative stress, liver damage, and increased cardiovascular risk — particularly in individuals with hemochromatosis or those not iron deficient.
The NIH Office of Dietary Supplements warns that excess iron intake can cause organ damage and is a leading cause of accidental supplement overdose in children.
→ Potential Contaminants – As part of the lymphatic and blood-filtering system, the spleen can accumulate heavy metals, pathogens, or other contaminants present in the source animal. Without rigorous third-party testing, these could be present in the final product.
A review in Food and Chemical Toxicology found that animal offal from contaminated environments can contain elevated heavy metals such as cadmium and lead (Zhang et al., 2014).
→ Hormone & Immune Modulation Risks – Peptides or bioactive compounds in spleen tissue may theoretically alter immune activity, but without dosing data or clinical safety studies, the effects could be unpredictable, especially for individuals with autoimmune conditions.
The British Journal of Nutrition cautions that immune-modulating compounds should not be assumed safe in supplement form without proper clinical validation (Calder, 2013).
→ No Standardization – Nutrient content in spleen capsules varies widely depending on the animal’s diet, age, and health, as well as processing methods. This makes it impossible for consumers to know how much of each nutrient they’re getting.
The U.S. Pharmacopeia states that without standardized manufacturing and verification, potency and composition in dietary supplements can fluctuate significantly from batch to batch.
→ Lack of Long-Term Safety Data – No studies have examined the long-term safety of spleen supplements in humans. This means risks may not be fully understood, especially when used alongside other nutrient-dense organ products.
The American Journal of Clinical Nutrition notes that safety cannot be assumed for supplements lacking long-term human data (Johnston, 2018).
Better Evidence-Based Alternatives
If you’re looking for the nutrients or performance benefits marketed by spleen supplements — like immune support, red blood cell production, and energy — there are clinically proven, transparent, and safer ways to achieve them without relying on unverified glandular extracts.
→ Comprehensive Nutrient Support – Instead of relying on unpredictable nutrient levels in spleen capsules, Swolverine’s Multivitamin delivers a clinically dosed, full-spectrum blend of essential vitamins and minerals in bioavailable forms to support immunity, energy, and overall wellness.
The NIH Office of Dietary Supplements stresses that meeting nutrient needs through standardized, well-characterized sources ensures safety and effectiveness.
→ B-Vitamins for Energy and Metabolism – If your goal is better energy production or red blood cell health, Swolverine’s B-Complex provides all eight essential B-vitamins, including clinically validated doses of vitamin B12 and folate.
Research confirms that oral B-vitamin supplementation supports red blood cell production and energy metabolism in deficient individuals (O’Leary & Samman, Nutrients).
→ Hormone and Recovery Support – Some spleen supplement marketing leans into vitality and endurance claims. For proven hormonal and recovery benefits, Swolverine’s ZMT combines zinc, magnesium, vitamin B6, and other research-backed ingredients to promote optimal testosterone, sleep, and muscle recovery.
Zinc and magnesium have been shown to support testosterone levels and strength in those with deficiencies (Prasad et al., Nutrition).
→ Cardiovascular and Mitochondrial Support – For heart health, anti-inflammatory benefits, and mitochondrial energy production, Swolverine’s Krill Oil provides highly bioavailable omega-3 fatty acids, while CoQ10 supports cellular energy and antioxidant protection.
Omega-3 supplementation has been linked to reduced cardiovascular risk (Bernasconi et al., JACC), and CoQ10 has been shown to improve exercise capacity and endothelial function (Sander et al., BioFactors).
→ Iron Supplementation for Deficiency – If you’re seeking spleen supplements for their iron content, targeted iron supplementation is safer and more effective, especially when guided by lab results.
A Cochrane Database review found that iron supplementation significantly improves ferritin and hemoglobin levels in deficient populations (Cancelo-Hidalgo et al., 2013).
→ Whole Food Approach – If you enjoy organ meats, fresh, well-sourced spleen consumed occasionally as part of a balanced diet can provide nutrients without the risks of concentrated capsule use.
Dietary diversity remains one of the strongest predictors of micronutrient adequacy (Ruel, Journal of Nutrition).
The Truth About Spleen Supplements
Spleen supplements are marketed as potent immune boosters and blood-building “superfoods,” but the science simply doesn’t support the hype. While fresh spleen is nutrient-rich, the freeze-dried capsule form is unstandardized, unproven, and carries potential risks that marketers rarely mention.
→ The Evidence Gap – There are no randomized controlled trials showing that spleen capsules improve immunity, red blood cell count, athletic performance, or any other claimed benefit in humans. Most promotional material relies on outdated theories like “like supports like” or extrapolations from animal studies.
Harvard Health Publishing confirms there is no credible scientific basis for the claim that consuming an animal organ strengthens the same organ in humans.
→ The Safety Concern – With unpredictable nutrient content, potential contaminants, and the risk of excessive iron intake, long-term daily use of spleen supplements can do more harm than good — especially without medical supervision.
The NIH Office of Dietary Supplements warns that iron overload can damage organs and increase disease risk.
→ A Smarter, Proven Approach – For immune, energy, and cardiovascular support that’s actually backed by research, Swolverine offers clinically dosed, transparent formulas like Multivitamin, B-Complex, ZMT, Krill Oil, and CoQ10. These deliver measurable results without the guesswork, risks, or pseudoscience.
At Swolverine, we don’t sell nostalgia — we sell science, transparency, and performance. Every product is formulated with clinically validated ingredients, clearly labeled dosages, and zero gimmicks — so you know exactly what you’re putting in your body, and why it works.
