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NCT Number: NCT04875715

Prospective Evaluation of Topical Almond Oil vs Hydroquinone

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.

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Key information

Age range

18 year and older

Sex eligibility

Female

Study type

Interventional

Phase

Phase 4

Primary location

UC Davis Department of Dermatology, Clinical Trials Unit

Sacramento, California, 95816, United States

Location status: Recruiting

Location contact

Alexis Carrington, MD

CONTACT

[email protected]

916-551-2636

Iryna Rybak, BS

CONTACT

[email protected]

916-551-2636

Raja K Sivamani, M.D.

PRINCIPAL_INVESTIGATOR

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Premenopausal women of Fitzpatrick skin types 3 to 6

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.

Treatment and study plan

Almond Oil

Other

Almond oil

Hydroquinone Topical

Drug

Hydroquinone 2% cream

Other names: Hydroquinone

Primary outcomes

  1. Intensity of facial pigment

    Time frame: 16 weeks

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

Secondary outcomes

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

    Time frame: 16 weeks

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

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

    Time frame: 16 weeks

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

  3. Appearance of facial redness

    Time frame: 16 weeks

    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).

  4. Subjective tolerability assessment

    Time frame: 16 weeks

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

  5. Intensity of facial pigment

    Time frame: 8 weeks

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

Study contacts

Contact information is provided by the study sponsor or research team.

Alexis Carrington

CONTACT

[email protected]

Iryna Rybak

CONTACT

[email protected]

916-551-2636

Sponsors and collaborators

Lead sponsor

University of California, Davis

Other

Registry information

Official study title

Prospective Evaluation of Topical Almond Oil vs Hydroquinone on the Appearance of Facial Pigmentation and the Stability of the Microbiome

Important dates

Study start
2021
Primary completion
2026
Study completion
2026
First posted
May 6, 2021
Registry last updated
Sep 12, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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