HELA Hair Clinical Safety Study (HRIPT)

Independent clinical study

Clinically tested.
Dermatologically reviewed.

HELA Hair commissioned a dermatologist-supervised Human Repeat Insult Patch Test to evaluate the skin tolerability and sensitization potential of its tested Black Shade formula.

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PCR Corp study HLHRIP1M · Manchester, United Kingdom · July–September 2025

Dr. David Wrone, board-certified dermatologist

Dr. David Wrone, MD

Principal Investigator & Consulting Dermatologist

106

participants completed the HRIPT study

50%

of the enrolled panel self-assessed as having sensitive skin

0

adverse events or adverse reactions reported

I–VI

Fitzpatrick skin types represented in the panel

Study design

How the HRIPT was conducted

The single-blind, single-center study used repeated occlusive patch applications based on a modified Draize method. The test article was diluted to 8% with deionized water according to the laboratory protocol.

1

Induction phase

Nine induction patches were applied over approximately three weeks.

2

Patch exposure

Induction patches were worn for approximately 47 or 71 hours under occlusive conditions.

3

Rest period

Participants completed a 14-day rest period after the induction phase.

4

Challenge phase

A 48-hour challenge patch was followed by readings approximately 1 and 48 hours after removal.

Study results

Low irritation and sensitization potential under the study conditions

No adverse events or reactions reportedThe report recorded no adverse events or adverse reactions during the study.
No questionable challenge reactionsNo questionable reactions were observed on challenge-phase days 38 and 40.
No study deviationsThe report states that no deviations occurred during study conduct.
Dermatologically reviewedThe final report was reviewed and signed by the principal investigator and quality assurance personnel.
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Participant panel

A broad range of skin types

The study enrolled adult men and women across Fitzpatrick skin types I through VI, including participants who described their skin as sensitive.

111participants enrolled
106participants completed
18–65participant age range
55participants self-assessed as having sensitive skin
I–VIFitzpatrick skin types represented
Subject demographics

All enrolled participants

The complete anonymized demographic table from the study panel, including gender, age, self-assessed skin type, and Fitzpatrick skin type.

Subject numbers are study codes and do not identify individual participants. Swipe horizontally on mobile to view every column.

Subject Gender Age Skin type Fitzpatrick
1 Male 33 Sensitive IV
2 Female 49 Normal I
3 Female 26 Sensitive III
4 Male 55 Normal III
5 Female 52 Sensitive IV
6 Male 45 Normal V
7 Female 41 Sensitive II
8 Female 35 Normal IV
9 Female 61 Sensitive III
10 Male 37 Normal II
11 Female 44 Sensitive VI
12 Female 46 Normal II
13 Female 59 Sensitive II
14 Female 37 Sensitive VI
15 Female 53 Normal II
16 Male 19 Sensitive V
17 Male 28 Normal V
18 Female 24 Sensitive VI
19 Female 33 Normal II
20 Female 20 Sensitive V
21 Male 37 Normal I
22 Female 28 Normal II
23 Female 20 Normal III
24 Female 40 Sensitive II
25 Female 25 Sensitive II
26 Male 19 Normal V
27 Male 37 Sensitive II
28 Female 29 Sensitive II
29 Male 25 Normal V
30 Male 27 Sensitive IV
31 Female 65 Normal V
32 Male 29 Normal III
33 Male 26 Sensitive I
34 Female 30 Normal II
35 Female 54 Sensitive I
36 Male 30 Normal V
37 Female 46 Sensitive II
38 Female 52 Sensitive IV
39 Male 24 Normal V
40 Male 43 Sensitive I
41 Female 32 Sensitive V
42 Male 49 Sensitive II
43 Female 26 Sensitive III
44 Male 40 Sensitive V
45 Female 18 Normal II
46 Female 41 Sensitive III
47 Female 31 Sensitive I
48 Male 49 Normal II
49 Female 27 Normal V
50 Male 39 Sensitive II
51 Female 42 Sensitive I
52 Female 23 Normal VI
53 Male 29 Normal II
54 Female 29 Normal III
55 Female 25 Sensitive I
56 Male 46 Sensitive II
57 Female 35 Normal IV
58 Female 42 Sensitive III
59 Female 34 Sensitive V
60 Female 29 Normal II
61 Male 27 Sensitive IV
62 Female 64 Sensitive II
63 Male 42 Sensitive VI
64 Female 28 Normal II
65 Female 58 Sensitive IV
66 Male 42 Sensitive III
67 Female 39 Normal I
68 Male 22 Sensitive VI
69 Female 57 Normal V
70 Female 23 Sensitive II
71 Male 24 Sensitive II
72 Female 43 Normal III
73 Female 25 Sensitive V
74 Male 22 Sensitive I
75 Female 38 Normal IV
76 Female 44 Sensitive VI
77 Male 43 Normal IV
78 Female 29 Normal II
79 Female 21 Sensitive III
80 Female 18 Normal V
81 Male 21 Normal II
82 Female 24 Normal III
83 Female 29 Sensitive I
84 Female 41 Normal IV
85 Female 19 Sensitive V
86 Male 25 Normal I
87 Female 28 Normal V
88 Male 29 Normal II
89 Male 26 Sensitive III
90 Female 28 Normal II
91 Female 47 Sensitive I
92 Male 25 Normal VI
93 Female 34 Normal VI
94 Female 32 Sensitive III
95 Male 29 Normal I
96 Female 18 Normal V
97 Female 31 Normal I
98 Female 29 Sensitive II
99 Male 23 Normal IV
100 Female 41 Normal VI
101 Female 37 Sensitive I
102 Female 27 Normal IV
103 Male 44 Normal III
104 Male 39 Normal V
105 Female 35 Sensitive VI
106 Female 23 Normal VI
107 Female 34 Sensitive II
108 Female 28 Normal III
109 Female 22 Normal VI
110 Female 28 Sensitive II
111 Male 49 Normal V
Study conclusion

What the results mean for HELA Hair

In this HRIPT, 106 participants completed the study, no adverse events or adverse reactions were reported, and no questionable reactions were observed during the challenge phase. Under the conditions of the study, the tested Black Shade formula demonstrated a low potential for irritation and sensitization.

For HELA Hair, these findings support a safety-first approach to at-home hair color: independent testing, dermatologist review, transparent study conditions, and representation across Fitzpatrick skin types I through VI.

Why choose HELA Hair?

The tested Black Shade formula completed an independent HRIPT.
The final report was dermatologically reviewed and quality-assurance audited.
The study included normal and self-assessed sensitive skin across skin types I–VI.
Simple at-home application with multiple natural-looking shade options.
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Study standards

Conducted with recognized research safeguards

The report describes the ethical, quality assurance, and good clinical practice framework used for this cosmetic-product tolerability study.

Declaration of Helsinki

The study report states that the research conformed to the applicable requirements of the Declaration of Helsinki and its amendments.

ICH Good Clinical Practice

Applicable ICH E6(R2) principles were followed as they relate to cosmetic and consumer-product research.

Quality assurance review

The final report was audited for the accuracy and completeness of the methods and data presented.

What does an HRIPT evaluate?

A Human Repeat Insult Patch Test evaluates skin tolerability and the potential for irritation and sensitization under controlled study conditions. It does not test hair-color performance, gray coverage, or color longevity.

Which HELA Hair product was tested?

The report identifies HELA Hair Black Shade Dye Shampoo, formula HH-B-2025-V1, batch BATCH01. The test article was diluted to 8% with deionized water according to the laboratory protocol.

Why was only the Black Shade selected for the HRIPT?

Black was selected because it is HELA Hair's deepest and most pigment-intensive shade, making it a practical representative formula for a rigorous tolerability assessment. The favorable result provides meaningful reassurance about the tested Black formula and HELA Hair's safety-first development approach. Because shades can differ, the HRIPT result formally applies to the specific Black Shade formula and batch tested; it should not be presented as separate clinical testing of every shade.

What makes HELA Hair different from conventional hair dyes?

HELA Hair's current formula is designed without PPD, ammonia, or parabens—three ingredients many hair-color shoppers specifically prefer to avoid. This helps distinguish HELA Hair from many conventional permanent dyes while keeping the experience focused on convenient at-home color. “Free from” does not mean allergy-free: always check the ingredient list for your specific shade and complete the required allergy alert test before every use.

Does this mean nobody can experience a reaction?

No. Individual sensitivities can vary, especially with hair-color products. Always follow the product directions and complete the required allergy alert or patch test before each use.

Were different skin tones represented?

Yes. The enrolled panel included participants across Fitzpatrick skin types I through VI.

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HRIPT assesses skin tolerability and sensitization; it does not measure product performance. Results apply to the tested article and the study conditions described above. Individual sensitivities vary. Always follow product directions and complete the required allergy alert test before each use. Data on file.
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