Integrative Therapeutics Similase GFCF - Digestive Enzyme Supplement for Adults - Supports Casein & Gluten Digestion* - Gas & Bloating Support* - Dairy-Free & Vegan - 120 Count (60 Servings)
$0.29/serving
Price verified Apr 22, 2026
Not evaluated by the FDA · Individual results may vary · Consult a healthcare provider before use
Our verdict
Microbial enzyme blend per 2-capsule serving (120 capsules, 60 servings) of DPP IV-Active Microbial Enzyme Blend (Protease with DPP IV Activity) per capsule from Integrative Therapeutics. Best for adults and…
Why we recommend this
Similase GFCF fills a genuine gap for individuals with gluten and casein sensitivity who experience digestive discomfort from trace exposures in social eating, cross-contamination, or dietary slip-ups. The DPP IV mechanism is clinically rational, the brand's 45+ year clinical heritage ensures enzyme quality, and the 892-review, 4.6-star performance confirms that this specialized product delivers real-world value for its target audience.
Check for interactions
Already taking other supplements or prescription medications? Add them below to check for documented interactions, severity, and clinical guidance.
Our database currently documents 137+ supplement and drug-category interaction pairs. Combinations not flagged here may still interact — always consult your healthcare provider before combining supplements, especially with prescription medications.
What to watch out for
The cost per serving is elevated compared to general digestive enzyme products, and the positioning requires careful consumer education — Similase GFCF is for gluten and casein sensitivity support, not celiac disease management. The lack of disclosed enzyme activity units prevents direct potency benchmarking.
Dose & form
- Serving
- Microbial enzyme blend per 2-capsule serving (120 capsules, 60 servings)
- Form
- Capsule
- Clinical range
- DPP IV enzyme activity is measured in HUT/GU units rather than mg; clinical products typically dose 500–2,000 HUT protease with DPP IV activity per serving for gluten/casein support
- Dose adequacy
- Specialized
- Supply
- 120 servings · $0.29/serving
- UPC
- 871791003866
Who it's best for
Adults and older children seeking targeted digestive enzyme support for gluten and casein digestion, particularly those with gluten and casein sensitivity who still consume trace amounts in their diet
Who should skip it
Individuals with diagnosed celiac disease who must follow strict zero-gluten protocols; Similase GFCF does not replace a gluten-free diet for celiac patients
Pros
- Specifically formulated with DPP IV enzymatic activity — the key enzyme pathway for breaking down proline-rich peptides from gluten and casein
- 892 reviews at 4.6 stars — strong validation signal for a specialized digestive enzyme from a clinical brand
- Vegan and dairy-free formula — appropriate for the lactose-sensitive population this product targets
- Integrative Therapeutics' clinical heritage since 1979 brings practitioner-grade enzyme quality to this specialized formulation
Cons
- 60 servings per 120-capsule bottle at $35.25 — $0.59 per serving is higher cost than general digestive enzyme products
- Not a replacement for celiac disease dietary management — must be clearly understood as a sensitivity-support product only
- Enzyme activity units (HUT, GU) are not disclosed in the listing, making potency comparison with competing products difficult
What customers say
4.6★ across 892 Amazon reviews. The most common questions from shoppers: re any potential interactions with medications, re any side effects from long-term use, and cause any digestive issues or side effects. Full answers in the FAQ below.
Frequently Asked Questions
What is the clinical dose for DPP IV-Active Microbial Enzyme Blend (Protease with DPP IV Activity)?
What is the clinical dose for DPP IV-Active Microbial Enzyme Blend (Protease with DPP IV Activity)?
Clinical trials typically use DPP IV enzyme activity is measured in HUT/GU units rather than mg; clinical products typically dose 500–2,000 HUT protease with DPP IV activity per serving for gluten/casein support. Integrative Therapeutics Similase GFCF delivers Microbial enzyme blend per 2-capsule serving (120 capsules, 60 servings), which we classify as Specialized relative to that range.
How does Integrative Therapeutics Similase GFCF compare to similar Capsule?
How does Integrative Therapeutics Similase GFCF compare to similar Capsule?
See the "Also consider" section below for two alternatives. Choose based on form preference (Capsule vs alternatives), dose adequacy, and third-party testing.
Is Integrative Therapeutics Similase GFCF third-party tested?
Is Integrative Therapeutics Similase GFCF third-party tested?
Yes — GMP Certified. Third-party testing verifies ingredient identity and label accuracy.
Does this work with Amazon Subscribe & Save?
Does this work with Amazon Subscribe & Save?
Yes — Amazon Subscribe & Save is available for this product. Enrolling locks in a recurring delivery at a reduced per-unit price.
Are there any potential interactions with medications?
Are there any potential interactions with medications?
Proteolytic enzyme supplements like Similase GFCF may theoretically enhance the absorption of certain medications by breaking down gut-barrier proteins — this can affect the absorption rate of antibiotics, anti-inflammatory drugs, and some immunosuppressants. Individuals on immunosuppressive therapy or with inflammatory bowel disease should consult their physician before using proteolytic enzyme supplements.
Are there any side effects from long-term use?
Are there any side effects from long-term use?
Microbial-derived digestive enzymes are generally well tolerated for long-term use at standard doses and do not accumulate in the body. Long-term enzyme supplementation does not suppress endogenous enzyme production in the pancreas, which is a common misconception. The most frequently reported long-term concern is mild GI adjustment during initial weeks of use.
Does it cause any digestive issues or side effects?
Does it cause any digestive issues or side effects?
Some users experience mild GI adjustment during the first 1–2 weeks of use — including loose stools or increased flatulence — as the gut microbiome and digestive pattern adapts. These effects typically resolve. Taking with food (as intended) minimizes initial GI adjustment. Serious adverse effects are uncommon at standard enzyme doses.
Can it be taken with other supplements or vitamins?
Can it be taken with other supplements or vitamins?
Similase GFCF is designed to work with meals and can be combined with probiotics, other digestive enzymes (amylase, lipase for broad-spectrum digestion), and standard vitamin and mineral supplements. It does not interfere with most supplement regimens. Avoid taking with very high-dose proteolytic enzyme supplements simultaneously, which may cause excessive protein breakdown.
Are there any specific instructions for taking it safely?
Are there any specific instructions for taking it safely?
Take 2 capsules at the beginning of each meal containing gluten or casein. Do not take on an empty stomach as the enzymes require substrate (food) to work. Not a treatment for diagnosed celiac disease — individuals with celiac must maintain a strict gluten-free diet regardless. Store away from heat and moisture to preserve enzyme activity.
How long until benefits are typically experienced?
How long until benefits are typically experienced?
Digestive enzyme effects are acute — they work during the meal in which they are taken, acting within the GI transit time of 30–90 minutes post-ingestion. Relief from bloating, gas, and digestive discomfort from gluten and casein exposure typically occurs within 1–3 hours of the meal. There is no build-up period required; benefit is meal-by-meal.
