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RecruitingNCT04875715Updated Sep 14, 2026

Prospective Evaluation of Topical Almond Oil vs Hydroquinone

A Phase 4 interventional study of Almond Oil and Hydroquinone Topical in Skin Pigmentation, sponsored by University of California, Davis. Recruiting at 1 site in United States. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-14.

Sponsored by University of California, Davis · Phase 4, Interventional, and Other

Phase
Phase 4
Study type
Interventional
Enrollment
50
Allocation
Randomized
Ages
18 Years and older
Sex
Female
01

Study summary

The purpose of this study is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.

Read the detailed description

The purpose of this experiment is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.

There will be a total of 50 subjects:

  • 25 randomized to receive almond oil nightly
  • 25 randomized to receive 2% hydroquinone nightly

Study Timelines:

  • The duration of an individual subject's participation will last from the day of the consent/screening (visit 1) until visit 5 where they will have images taken and measurements collected to assess skin pigment, skin hydration, sebum excretion rate.
  • The duration of participation is 4 months.
  • The estimated time for the investigators to complete primary analysis is 2 years.
02

Conditions studied

  • Skin Pigmentation

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03

Who can participate

Ages eligible
18 Years and older
Sexes eligible
Female
Accepts healthy volunteers
No

Inclusion criteria

  • Premenopausal women of Fitzpatrick skin types 3 to 6

Exclusion criteria

Exclusion Criteria:

  • Those with a nut allergy
  • Smoking is an independent risk factor and serves as a confounder for the development of facial aging [18]. Therefore current smokers, those that have smoked within the past year, and former smokers with greater than a 20 pack year history of smoking will be excluded.
  • Those with an autoimmune photosensitive condition or a known genetic condition with a deficiency in collagen production (such as Ehlers-Danlos syndrome) will be excluded as this can be a confounder for facial photoaging.
  • Hormonal medications or therapies will not be allowed unless they have been stable on their medications for at least 2 months. Examples include oral contraceptives, progesterone-based injections, and estrogen based hormonal replacement therapy.
  • Those who have undergone any cosmetic procedures to the face in the 4 months prior to enrollment in the opinion of the investigator. People that have undergone deeper chemical peels (TCA based peels) within 1 year prior to enrollment will also not be eligible.
  • Individuals who are unwilling to discontinue vitamin E containing supplements and food sources during the washout and intervention.
  • Individual who are unwilling to discontinue topical cosmetic products during the duration of the study.

  • Individuals who are not willing to engage in a two-week washout on topical treatments known to affect facial pigmentation and these agents will be restricted during the study period as well. These include topicals that contain:

    • Retinoids such as tretinoin, adapalene, retinol.
    • Antioxidant ingredients such as vitamin C or vitamin E.
    • Pigment-reducing agents such as hydroquinone, azelaic acid, kojic acid per the discretion of the investigator except for the hydroquinone that is provided in this study.
    • Topicals that contain a nut oil or nut extract as part of their ingredient list.
  • Furthermore, subjects will be asked to refrain from use of any other topical products for one week prior to each visit apart from the study agents supplied from this study.
04

Study design

Phase
Phase 4
Primary purpose
Other
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
50 participants (estimated)

Study arms

  • Experimental
    Almond oil

    Almond Oil Pressed Cold

    Other: Almond Oil

  • Active comparator
    Hydroquinone

    Hydroquinone 2% cream

    Drug: Hydroquinone Topical

Interventions

  • OtherAlmond Oil

    Almond oil

  • DrugHydroquinone Topical

    Hydroquinone 2% cream

    Also known as: Hydroquinone

05

What researchers measure

Primary outcomes

  1. Intensity of facial pigment

    Facial images will be obtained and analyzed with the BTBP image analysis system

    Time frame: 16 weeks

Secondary outcomes

  1. Shifts in the microbiome diversity (Shannon index as an example)

    The skin microbiome will be analyzed to assess any changes after topical almond oil application, compared to the use of topical hydroquinone.

    Time frame: 16 weeks

  2. Quantification for the presence of species within the genus Cutibacteria, Staphyloccoccus, and Ralstonia

    The skin microbiome will be analyzed to assess the presence of species within the genus Cutibacteria, Staphyloccoccus, and Ralstonia

    Time frame: 16 weeks

  3. Appearance of facial redness

    The research team will quantify the presence of facial redness with a SkinColorCatch from Delfin Technologies. This will measure the RGB colors and average them from each participant for each of the visits. Skin pigment, including the presence of redness, will be measured using a SkinColorCatch from Delfin Technologies. This device shows the RGB Colors, CIE L\*a\*b\* and L\*c\*h\* color space coordinates when the device is applied to the skin.Included is the link to the device (http://www.truesystem.co.kr/product/pdf/SkinColorCatch%20Brochure%202016.pdf).

    Time frame: 16 weeks

  4. Subjective tolerability assessment

    A questionnaire that assesses for stinging, itching, and burning will be utilized.

    Time frame: 16 weeks

  5. Intensity of facial pigment

    Facial images will be obtained and analyzed with the BTBP image analysis system

    Time frame: 8 weeks

06

Study locations

1 of 1 sites recruiting
  • UC Davis Department of Dermatology, Clinical Trials Unit
    Sacramento, California 95816, United States
    Recruiting
07

References and documents

Individual participant data

Plan to share: No

08

Registry details

Key details

Study ID
NCT04875715
Lead sponsor
University of California, Davis
Responsible party
Sponsor
First posted
May 6, 2021
Start date
Jul 1, 2021
Primary completion
Dec 1, 2026 (estimated)
Completion
Dec 1, 2026 (estimated)
Last update
Sep 14, 2026

Study contacts

Iryna Rybak
Contact
irybak@ucdavis.edu
916-551-2636
Alexis Carrington
Contact
aecarrington@ucdavis.edu
Raja Sivamani, MD MS AP
principal investigator · UC Davis Dermatology

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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