Is Dymatize ISO100 really lactose-free?

Yes. ISO100 uses cross-flow microfiltration followed by full enzymatic hydrolysis, which removes all detectable lactose. This distinguishes it from standard WPI products (which retain trace lactose) and makes it safe for severe lactose intolerance. The zero-lactose claim is accurate and verifiable through Dymatize's Informed Sport batch records.

Is Dymatize ISO100 third-party tested?

Yes — Dymatize ISO100 carries Informed Sport certification and NSF Certified for Sport, making it one of very few proteins with dual-certification. This is particularly important for NCAA athletes, professional sports league athletes, and military personnel where NSF Sport is specifically required.

Which ISO100 flavour is best?

Fudge Brownie is consistently ranked best-in-class across independent tastings — it effectively masks the mild bitterness characteristic of hydrolyzed proteins with rich cocoa notes. Chocolate Peanut Butter is a close second. Gourmet Vanilla is the safest choice for those who mix protein into recipes. Birthday Cake is polarising.

Dymatize ISO100 Hydrolyzed Whey Review 2026 — Zero Lactose WPI Tested

Dymatize

ISO100 Hydrolyzed Whey Protein

100% Hydrolyzed WPI Zero Lactose · Zero Fat Informed Sport NSF Certified for Sport

25g

Protein / Serving

110

Calories

Lactose

$1.50

Price / Serving

Buy on Amazon →

The Verdict

fitlabreviews Verdict — May 2026

The definitive zero-lactose protein — and one of the very few that dual-certified athletes can actually trust.

ISO100 is not the protein for everyone. It does not build more muscle than ON Gold Standard Whey for lactose-tolerant users training once daily — the peer-reviewed literature is clear on this.¹ What it does is deliver 25g of 100% hydrolyzed WPI with zero detectable lactose, in a flavour range that is genuinely best-in-class for a zero-lactose protein (Fudge Brownie is outstanding), at a price premium of ~$0.62/serving over GS Whey.

The dual Informed Sport + NSF Certified for Sport certification is a material differentiator. Most protein powders hold one or the other. ISO100 is one of a small group that holds both — making it the correct choice for NCAA athletes, professional sports league athletes, and military personnel where both programs are cited in governing body documentation.

The honest verdict: buy ISO100 if you have lactose sensitivity, are a certified athlete in a dual-cert program, or train twice daily. For everyone else, ON Gold Standard Whey is the smarter purchase.

Category Scores

Scored per FitLab methodology — formula quality, evidence, transparency, practical use, value.

9.0/10

Overall Score

Formula Quality

9.5

Clinical Evidence

9.0

Transparency

8.8

Palatability

8.8

Value for Money

7.8

✓

What Works

100% hydrolyzed WPI — cross-flow microfiltration removes all lactose; zero fat
Dual certification: Informed Sport + NSF Certified for Sport — rare in the category
12+ flavours including Fudge Brownie (best-in-class for a zero-lactose protein)
25g protein per 31g serving — clean, consistent label across all flavours
5.5g BCAAs including ~2.7g leucine — above mTOR activation threshold²
Smooth, grit-free texture — hydrolyzed proteins dissolve completely
Available in multiple sizes from 1lb to 5lb — flexible purchasing

✗

What Doesn't

~$0.62/serving premium vs ON GS Whey — ~$19/month extra at daily use
Mild bitterness in some flavours — inherent to hydrolysis; Vanilla flavours more noticeable
No muscle-building advantage over GS Whey for once-daily lactose-tolerant users¹
Contains soy lecithin — relevant for soy-allergic individuals
Some flavours (Birthday Cake, Peanut Butter) are polarising

Key Numbers at a Glance

25g

Protein / Serving

Lactose

Fat

110

Calories

5.5g

BCAAs

2×

Certifications

12+

Flavours

$1.50

Cost / Serving

Macro & Value Charts

Protein per Serving — Top WPI Products Compared

Per-serving protein (g) across the leading hydrolyzed and standard isolate options. Current label data, May 2026.

Lactose & Fat per Serving — Purity Comparison

Lower = better for lactose sensitivity and lean-phase macro precision. ISO100 and Hydrowhey are the only products with true zero lactose.

Cost per Gram of Protein — Value Efficiency

Cents per gram of protein delivered, May 2026 Amazon pricing. ISO100's premium is visible but moderate vs other isolates.

Formula Analysis — What Makes It Different

The ISO100 label lists a single protein source: Hydrolyzed Whey Protein Isolate. No concentrate, no caseinate, no blends. Every gram of protein has been through two processing steps: cross-flow microfiltration (removes fat and lactose at the membrane level) and full enzymatic hydrolysis (breaks remaining protein chains into di- and tripeptides).

📚

What the science says about hydrolysis speed

Tang et al. (2009) confirmed hydrolyzed WPI produces peak plasma amino acids ~25 minutes faster than intact WPI. At the 3-hour MPS measurement window — the outcome that matters for muscle building — there was no statistically significant difference between hydrolyzed WPI and standard WPI at matched doses. The speed advantage matters for twice-daily athletes. For once-daily users, it primarily improves digestive comfort.

Cross-flow microfiltration produces WPI at 90%+ protein concentration, removing virtually all fat and lactose. Full enzymatic hydrolysis then breaks the remaining intact protein chains into di- and tripeptides. The result is the fastest-absorbing commercially available whey protein with zero detectable lactose — confirmed by Dymatize's third-party testing program.

✓ 100% hydrolyzed ✓ Zero lactose verified ✓ Zero fat

Used for mixability — prevents clumping and ensures the powder disperses cleanly in water. The specific lecithin source varies by flavour; some use soy lecithin. Individuals with soy allergies should check individual flavour labels. At these doses, lecithin has no meaningful nutritional or performance impact.

Check soy allergy — some flavours use soy lecithin

Nutrition Facts — Fudge Brownie (per 31g serving)

Nutrient	ISO100	ON GS Whey	ON GS Isolate	ON Hydrowhey	Verdict
Protein	25g	24g	25g	30g	Above MPS threshold
Carbohydrates	2g	3g	1g	3g	Very low
Fat	0g	1.5g	0g	1.5g	Zero fat
Calories	110	120	110	160	Lean profile
Lactose	0g ✓	Low	Trace	0g ✓	Only true zero-lactose
BCAAs	5.5g	5.5g	5.5g	8.8g	Above leucine threshold
Cert	IS + NSF	IS + NSF	IS only	IS only	Dual certified

Flavours Ranked — 12 Tested

Dymatize has the strongest flavour range of any zero-lactose protein powder. The full hydrolysis process introduces mild bitterness, but Dymatize's flavouring team manages it significantly better than competitors — particularly in the chocolate variants.

01 Fudge Brownie Best in class

02 Chocolate Peanut Butter Highly recommended

03 Chocolate Coconut Recommended

04 Gourmet Vanilla Best for recipes

05 Strawberry Recommended

06 Cookies & Cream Recommended

07 Orange Dreamsicle Polarising

08 Peanut Butter Polarising

09 Birthday Cake Polarising

10 Cinnamon Bun Decent

11 Fruity Pebbles Novelty only

12 Unflavored For recipes

⚠️

Vanilla Flavours — Taste Note

Vanilla-based flavours expose the hydrolysis bitterness more than chocolate variants. If you are bitterness-sensitive and prefer vanilla, mix with unsweetened almond milk (cold) rather than water — it substantially reduces the bitter back-note without meaningfully slowing absorption.

Who Should Buy / Who Should Skip

✓ Buy ISO100 If…

You have lactose sensitivity or intolerance — this is the most thoroughly proven zero-lactose option
You are an NCAA, professional sports, or military athlete requiring NSF Certified for Sport specifically
You want the widest best-tasting flavour selection in a zero-lactose protein
You train twice daily — faster absorption is genuinely meaningful at that cadence
You compete in physique sports and need precise macro tracking with zero fat variability

✗ Skip — Buy GS Whey If…

You're lactose-tolerant and train once daily — identical MPS outcomes at $0.62 less per serving
You want maximum flavour variety without premium pricing — GS Whey has 15+ options
You're budget-conscious — GS Whey saves ~$19/month at daily use
You have a soy allergy and can't verify individual flavour lecithin sources
You mix protein with milk — negates the lactose-free advantage and absorption speed benefit

Third-Party Testing — Dual Certification Explained

✓

Informed Sport — Batch-level certification

Every production batch tested at LGC Group's accredited lab for 250+ WADA-prohibited substances. Batch certificates publicly verifiable by lot number at informed.sport. This is the most common protein powder certification.

✓

NSF Certified for Sport — Facility + product certification

NSF Sport tests the product AND audits the manufacturing facility. This two-layer approach is required by NCAA, MLB, NFL, NBA, NHL, and MLS governing bodies. Very few protein powders maintain both certifications simultaneously — ISO100 is one of them.

How It Compares

Product	Protein	Lactose	Certs	Flavours	Price/Srv	Best For
Dymatize ISO100 (this review)	25g	Zero ✓	IS + NSF	12+	$1.50	Lactose-sensitive, certified athletes
ON GS 100% Whey	24g	Low	IS + NSF	15+	$0.88	Best value, general fitness
ON GS 100% Isolate	25g	Trace	IS only	2	$1.75	Comp prep, mild intolerance
ON Platinum Hydrowhey	30g	Zero ✓	IS only	2	$1.57	Twice-daily athletes
TL 100% Whey Isolate	28g	Trace	IS only	10+	$2.00	No artificial sweeteners

⭐ This Review

Dymatize

ISO100 Hydrolyzed Whey

Protein25g

LactoseZero ✓

Score9.0/10

Optimum Nutrition

Gold Standard 100% Whey

Protein24g

CertsIS + NSF

Score9.8/10

Optimum Nutrition

Gold Standard 100% Isolate

Protein25g

Efficiency92%

Score9.0/10

Transparent Labs

100% Whey Protein Isolate

Protein28g

SweetenerStevia

Score9.1/10

Frequently Asked Questions

Yes — genuinely zero lactose. Cross-flow microfiltration removes all detectable lactose during WPI production, and full enzymatic hydrolysis eliminates any remaining trace amounts. This distinguishes ISO100 from standard WPI products (which retain trace amounts) and from GS Isolate (which retains trace amounts despite being mostly lactose-free). ISO100 is the correct choice for severe lactose intolerance.

No — not for once-daily training athletes with adequate protein intake. Tang et al. (2009) in the Journal of Applied Physiology found no statistically significant difference in muscle protein synthesis at 3 hours between hydrolyzed WPI and standard WPI at matched doses. ISO100's advantages are zero lactose, faster absorption (relevant for twice-daily athletes), and dual third-party certification. Not superior muscle-building outcomes for general users.

Fudge Brownie consistently ranks best — the rich cocoa profile effectively masks the mild bitterness inherent to full hydrolysis. Chocolate Peanut Butter is a close second. For vanilla preferences, Gourmet Vanilla is the most neutral option and works well in recipes. Birthday Cake and Peanut Butter are polarising — we'd recommend trialling a smaller size first.

Dymatize maintains dual certification because different governing bodies require different programs. NCAA institutions typically cite NSF Certified for Sport. WADA-governed international sports typically accept Informed Sport batch certification. Dual-certification covers both bases — making ISO100 one of the very few proteins usable across all major sport types including collegiate, professional, international, and military contexts.

ISO100 costs approximately $1.50–$1.80 per serving depending on size (1lb to 5lb). ON Gold Standard Whey costs $0.88–$1.00 per serving. The premium is approximately $0.62–$0.90 per serving — roughly $19–$27 more per month at once-daily use. This premium is justified for lactose-sensitive users and certified athletes. For lactose-tolerant recreational gym-goers, GS Whey delivers equivalent muscle-building outcomes at significantly lower cost.

References

Tang JE, et al. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol. 2009;107(3):987–992. DOI · PubMed

Norton LE, Layman DK. Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. J Nutr. 2006;136(2):533S–537S. DOI

Hulmi JJ, et al. Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy. Nutr Metab. 2010;7:51. DOI

Boirie Y, et al. Slow and fast dietary proteins differently modulate postprandial protein accretion. Proc Natl Acad Sci USA. 1997;94(26):14930–14935. DOI

Churchward-Venne TA, et al. Supplementation of a suboptimal protein dose with leucine or essential amino acids. J Physiol. 2012;590(11):2751–2765. DOI