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Source Plus — Dogs And Puppies (For Dogs SOURCE PLUS)

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Source Plus For Dogs SOURCE PLUS! GIVES DOGS THE MICRONUTRIENT EDGE...

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Reviewed by Ann Pruitt, InfoHorse.com · Updated May 2026
SOURCE PLUS for Dogs micronutrient supplement container
SOURCE PLUS for Dogs micronutrient supplement container
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Source Plus For Dogs
SOURCE PLUS! Gives Dogs THE Micronutrient Edge...

About Our Company

More than two decades ago SOURCE president and founder, Susan Domizi was competing on her eventing horse, Hull, with hopes of being on the US Equestrian Olympic Team. "My horse [Hull] had hoof problems and couldn't maintain his body weight. He received the finest feeding program and veterinary care available. I suspected a nutrient deficiency and set out to find something to help him." She found a great deal of Norwegian and Japanese research on seaweeds that scientists and agriculturists here had been able to duplicate. In addition to using information learned while earning a degree from Columbia University in New York, she studied all available data to determine what the American studies had missed. She used this information as a starting point for developing other approaches..

By trying different kinds of seaweeds, different blends, different methods of processing and constantly analyzing the findings she came up with a finely ground, dry mixture that she put in her horse's food. Her horse began to thrive. And that was the first serving of the product that was later to become SOURCE.

SOURCE PLUS! Gives Dogs THE Micronutrient Edge...

Dogs can thank horses for SOURCE PLUS! a nutritional advance that helps dogs cope with the consequences of increasing micronutrient deficiencies in their foods. Horsemen impressed with the results of adding SOURCE micronutrients to their horse's diet, reported similar improvements when they fed it to their dogs. Now new SOURCE PLUS! formulated just for dogs provides the same all natural, broad-spectrum micronutrients from selected seaweeds plus the added benefits of yeast cultures, brewers yeast, garlic powder, vitamin E, zinc and natural beef flavor.

Depleted agricultural soils mean essential micronutrients are missing in even the finest dog foods. The SOURCE micronutrients are concentrated from seaweeds grown in nutrient-rich ocean waters. Careful selection, harvesting, and low temperature dehydration capture these nutrients at their peak. SOURCE PLUS! concentrates all the ocean's bounty and then adds other important natural ingredients to help young dogs grow strong and healthy and mature dogs feel their best. Dog owners' reports include superior glossy coats, healthy skin condition, successful breedings, and improved temperment and appetites.

What Is In Source Plus For Dogs?

Dehydrated seaweed meals, yeast culture, brewer's yeast, garlic powder, vitamin E, zinc proteinate, natural flavor carefully formulated to help bring optimal health and condition to your dog .

The Source Guarantee

We want every person to have the opportunity to see for themselves the effectiveness of the Source micronutrients found in all of our products. If you are not satisfied with any of the products for any reason, your money will be refunded in full - no strings attached. (Simply enclose proof of purchase.)

Order SOURCE PLUS For Your Dogs-- Today!

Every dog in the world can greatly benefit from the careful selection of ingredients that make up SOURCE PLUS for your dog. Be sure to order today-- also available at Amazon, Valleyvet and many fine dealers!





SOURCE PLUS for Dogs micronutrient supplement container
SOURCE PLUS for Dogs micronutrient supplement container

What exactly is SOURCE PLUS for Dogs?

SOURCE PLUS for Dogs is an all-natural micronutrient supplement built on the same dehydrated ocean-seaweed concentrate that made SOURCE a fixture in barns for half a century, then fortified specifically for canine needs. To the broad-spectrum seaweed base, the "Plus" formula adds Yeast Culture, Brewer's Yeast, Garlic Powder, Vitamin E and Zinc, addressing the trace-element gaps that even premium commercial dog foods can leave behind. It carries no artificial colors, flavoring, preservatives, synthetics or drugs, and the company guarantees your satisfaction with the results with no time limit.

SOURCE PLUS for Dogs 5 lb size with dog
SOURCE PLUS for Dogs 5 lb size with dog
Who makes it, and where did SOURCE come from?
SOURCE Micronutrients LLC is based at 101 Fowler Road, N. Branford, CT 06471, and has been making micronutrient supplements since SOURCE was formally introduced in December 1975. Founder and president Susan Domizi developed the original formula to rescue her eventing horse, Hull, who battled hoof problems and could not hold weight despite the finest feeding and veterinary care. Drawing on Norwegian and Japanese seaweed research and her Columbia University background, she blended cold-water ocean seaweeds into a finely ground concentrate, and Hull recovered so dramatically that he was named 1969 U.S. Intermediate Horse of the Year in Combined Training.

SOURCE micronutrient products for horses full lineup
SOURCE micronutrient products for horses full lineup
What is in the bag, and what does the analysis guarantee?
The dog formula combines dehydrated seaweed meals, yeast culture, brewer's yeast, garlic powder, vitamin E, zinc proteinate and natural flavor. The guaranteed analysis includes Zinc at 5,600 mg/kg, Iodine at 350 mg/kg, Iron at 250 mg/kg, Magnesium at 5,000 mg/kg, Potassium at 1.4%, Sodium at 1.4%, and Vitamin E at a minimum of 3,250 IU/kg. Because the seaweed base carries at least 60 elements in biologically active form rather than a handful of isolated synthetics, the supplement targets the subtle "subclinical" deficiencies that standard vitamin-mineral products miss.

SOURCE Original powder concentrate open container
SOURCE Original powder concentrate open container

How micronutrients work where ordinary supplements stop

Most supplements concentrate on the 14 recognized essential trace elements; SOURCE goes further, delivering those plus 21 additional trace elements still under study and unidentified nutritional factors, all in the naturally chelated, biologically active form ocean seaweeds provide. Dog owners report the same cascade of benefits horsemen first noticed: superior glossy coats, healthy skin, successful breedings, steadier temperament, sharper appetites and better overall condition in both young and mature dogs. The benefits were in fact discovered backward, when horse customers fed SOURCE to their dogs and reported shinier, thicker coats.

How much to feed, and how long a container lasts
Daily amounts scale with body weight: roughly 1 to 1 and 1/3 teaspoons for a 15-lb dog, 2 to 2 and 2/3 teaspoons at 30 lbs, up to about 6 teaspoons to 2 tablespoons for dogs 90 lbs and over. Because the dose is small, the supplement is genuinely economical: a 12 oz. container lasts a 15-lb dog about 113 days, and a 5 lb. container stretches to roughly 756 days. There is nothing to mix or measure beyond a daily scoop topped on the regular meal.

Sizes, pricing, and how to order
SOURCE PLUS for Dogs is sold in 12 oz., 5 lb. and 20 lb. sizes, starting at $16.47 for the 12 oz. container, with the full range running up to $171.92 for the largest size. Order direct at www.4source.com/shop/ or call SOURCE toll-free at (800) 232-2365 (direct line (203) 488-6400), Monday through Friday, 9 a.m. to 5 p.m. Eastern. SOURCE Micronutrients is a proud founding member of the National Animal Supplement Council (NASC), audited and certified, and the company stands behind every container with its long-standing no-time-limit money-back guarantee.
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The Solution Section (FAQ)
What is Source Plus for Dogs?
Source Plus is an all-natural, broad-spectrum micronutrient supplement for dogs made from selected seaweeds. It adapts the same SOURCE micronutrient approach horsemen used on their horses, with a formula created specifically for dogs.
What is in Source Plus for Dogs?
It contains dehydrated seaweed meals, yeast culture, brewer's yeast, garlic powder, vitamin E, zinc proteinate, and natural flavor. The seaweed micronutrients are concentrated from seaweeds grown in nutrient-rich ocean waters, and the dog formula also includes natural beef flavor.
Why would my dog need a micronutrient supplement if I already feed a quality food?
Source Plus is built around the idea that depleted agricultural soils mean essential micronutrients are missing in even the finest dog foods. The supplement concentrates broad-spectrum micronutrients from ocean seaweeds to help fill that gap.
What results do dog owners report from feeding Source Plus?
Owner reports include superior glossy coats, healthy skin condition, successful breedings, and improved temperament and appetites. The formula is intended to help young dogs grow strong and healthy and to help mature dogs feel their best.
How are the seaweed micronutrients in Source Plus processed?
The seaweeds are grown in nutrient-rich ocean waters, then captured at their peak through careful selection, harvesting, and low-temperature dehydration. This processing is meant to preserve the concentrated micronutrients SOURCE is known for.
Who created SOURCE and its dog supplement?
SOURCE was developed by company president and founder Susan Domizi, who began the work more than two decades ago while competing on her eventing horse, Hull, that had hoof problems and trouble maintaining weight. After studying Norwegian and Japanese seaweed research and drawing on her Columbia University degree, she developed the finely ground seaweed mixture that became SOURCE; the dog formula grew out of horsemen feeding it to their own dogs.
Is there a guarantee, and where can I buy Source Plus for Dogs?
Yes. The Source Guarantee promises a full refund on any product, for any reason, with proof of purchase and no strings attached. Source Plus for Dogs is also available at Amazon, ValleyVet, and many fine dealers.
How do I order Source Plus or learn more?
You can order Source Plus for Dogs or read the full product details at https://www.4source.com. Source is located at 7 Industrial Parkway, Brunswick, Maine 04011, and you can reach the staff at 800-232-2365.
How is SOURCE PLUS different from a regular vitamin and mineral supplement?
Ordinary supplements concentrate on a short list of recognized vitamins and minerals, while SOURCE delivers at least 60 elements and their associated micronutrient compounds in biologically active form. This includes the 14 recognized essential trace elements, 21 more under study, and unidentified nutritional factors. The seaweed base provides these in a naturally chelated form rather than as isolated synthetics.
What ingredients are in SOURCE PLUS for Dogs?
The formula contains dehydrated seaweed meals, yeast culture, brewer's yeast, garlic powder, vitamin E, zinc proteinate and natural flavor. There are no artificial colors, flavoring, preservatives, synthetics or drugs. The seaweed concentrate is the same base used in the original SOURCE supplement for horses.
What benefits do dog owners report?
Reported improvements include superior glossy coats, healthy skin condition, successful breedings, improved temperament and appetites, and better overall health in both young and mature dogs. These benefits were first noticed when horse customers began feeding SOURCE to their dogs and saw shinier, thicker coats. The company keeps notebooks of unsolicited customer testimonials at its headquarters.
How much SOURCE PLUS should I feed my dog?
Daily amounts scale with body weight. A 15-lb dog gets about 1 to 1 and 1/3 teaspoons, a 30-lb dog 2 to 2 and 2/3 teaspoons, a 45-lb dog about 1 tablespoon, and dogs 90 lbs and over up to 2 tablespoons daily. The supplement is simply topped on the dog's regular food once a day.
How long does a container of SOURCE PLUS last?
Because the daily dose is small, the supplement is economical. A 12 oz. container lasts a 15-lb dog approximately 113 days, and a 5 lb. container lasts roughly 756 days for the same size dog. Larger dogs use proportionally more, so duration scales with the feeding chart.
What sizes and prices are available?
SOURCE PLUS for Dogs comes in 12 oz., 5 lb. and 20 lb. sizes. Pricing starts at $16.47 for the 12 oz. container and runs up to $171.92 for the largest size. You can order all sizes directly from the SOURCE online shop.
Who makes SOURCE PLUS and where are they located?
SOURCE PLUS is made by SOURCE Micronutrients LLC, located at 101 Fowler Road, N. Branford, CT 06471 USA. The company was founded by Susan Domizi and has been producing micronutrient supplements since 1975. Products are now sold worldwide for horses, dogs and people.
What is the story behind SOURCE?
Founder Susan Domizi created SOURCE to help her eventing horse, Hull, who suffered hoof problems and could not maintain weight despite excellent feeding and veterinary care. Drawing on Norwegian and Japanese seaweed research and her Columbia University education, she developed a finely ground seaweed concentrate. Hull recovered so dramatically that he was named 1969 U.S. Intermediate Horse of the Year in Combined Training.
When did SOURCE first come to market?
SOURCE was formally introduced in December 1975, after years of word-of-mouth demand from the equestrian community. It became the first equine nutritional supplement to offer a no-questions-asked money-back guarantee, a move competitors and bankers warned against at the time. The company has now been in business for roughly 50 years.
Is SOURCE certified by any regulatory body?
Yes. SOURCE Micronutrients is a proud founding member of the National Animal Supplement Council (NASC) and is audited and certified under its program. The NASC quality seal reflects compliance with the council's standards for animal supplement manufacturers. This certification covers the company's horse, dog and people products.
What does the guaranteed analysis of SOURCE PLUS for Dogs include?
Key guaranteed levels include Zinc at 5,600 mg/kg, Iodine at 350 mg/kg, Iron at 250 mg/kg, Magnesium at 5,000 mg/kg, Potassium at 1.4%, Sodium at 1.4%, and Vitamin E at a minimum of 3,250 IU/kg. It also lists Calcium at 0.4 to 0.9%, Phosphorus at 0.4%, Manganese at 35 mg/kg and Copper at 5 mg/kg. These come largely from the natural seaweed base.
Is there a satisfaction guarantee?
Yes. SOURCE guarantees your satisfaction with the results with no time limit. This no-questions-asked money-back guarantee has been a hallmark of the company since it launched in 1975. It applies to the dog supplement as well as the equine line.
Where does the seaweed in SOURCE come from?
The supplement is concentrated from nutrient-rich cold-water ocean seaweeds, sustainably harvested and refined over decades. Susan Domizi developed her own dedicated sources of supply early on because she found she could not reliably source the quality she needed elsewhere. The seaweeds are processed into pure dehydrated meals with no additives.
Can SOURCE be used for animals other than dogs and horses?
SOURCE products are made for horses, dogs and people, with separate formulations for each. The original equine line includes SOURCE Original powder, SOURCE Nuggets, and the FOCUS HF (hoof), FOCUS SR (senior) and FOCUS WT (weight) formulas. There is also a MICRO-MAX product for people.
How do I order SOURCE PLUS for Dogs or contact the company?
You can order directly at www.4source.com/shop/ or call toll-free at (800) 232-2365, with a direct line at (203) 488-6400. Email inquiries go to [email protected]. Business hours are Monday through Friday, 9 a.m. to 5 p.m. Eastern, and the company is closed weekends and holidays.
Does SOURCE PLUS contain any drugs or artificial additives?
No. SOURCE PLUS for Dogs contains no artificial colors, flavoring, preservatives, synthetics or drugs. It is built entirely on natural seaweed meals plus yeast culture, brewer's yeast, garlic powder, vitamin E, zinc proteinate and natural flavor. This all-natural approach has defined the brand since its founding.
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